Furnace burning pulverized fuel



Oct. 30, 1928. 1,689,675

w. LULOFS FURNACE BURNING PULVERIZED FUEL Filed Oct. 18, 1923iffo/f/wsys the stoker.

Patented Oct. 30, 1928.

UNITED STATES WARNER LULOFS, OF AMSTERDAM, NETHERLANDS.

FURNACE BURNING PULVERIZED FUEL.

Application filed October 18, 1923, Seria1 No. 669,263, and in GreatBritain October 23, 1922.

The combustion chamber in a boiler furnace having a mechanical stoker onwhich the fuel is substantially completely burnt by air passing throughthe stoker, is used. at greatest efficiency only when there is a certainminimum proportion of uncombined oxygen in the gases leaving thechamber. There is difficulty in attaining this efficiency because, forseveral reasons, combustion on the stoker is not satisfactory unless anexcess of air is passing, particularly at the rear of the stoker.

This invention increases the combustion in the chamber, thusreducing theuncombined oxygen in the combustion gases, by injecting pulverized fuelinto the furnace, in an improved manner, namely in such a manner thatthe-pulverized fuel is suspended in the combustion gases over therearpart of The degree of pulverization should be such that the proportionof fuel which falls upon that burning on the stoker is small. There isthus obtained a cloud of fuel at the place where there is mostuncombined oxygen.

One advantage of this extra combustion over the rear part of the grateis that there is produced the effect of those special devices, such asan extended arch, intended to radiate upon the fresh fuel fed to thestoker and thereby to ensure its rapid ignition.

Another advantage is since there is sufficient radiation from the fuelon the stoker to ensure ignition of the injected. powder, the injectionmay be intermittent and a means is afforded for forcing the boiler byincreasing the combustion in the combustion chamber when an over-loadhas to be met. Finally the regulaton of the air supply to the furnace tothat necessary for combustion is facilitated because the excess of aircontained in the gases leaving the mechanical stoker can be used for thecombustion of the pulverized fuel.

The invention includes the combination with a boiler furnace chamber ofa travelling grate stoker therein and a pulverizer adapted to pulverizefuel and to inject it and Fig. 2 is an irregular transverse section,substantially on the line 2-2 of Fig. 1.

At the rear of the furnace is a fuel pulverizcr (l of a rotary typedriven by a motor 6. The pulverizer projects the fuel into a pipe f fromwhich spring a number of jetpipes extending into the furnace at a levelabove the traveling grate.

Having thus described the nature of the said invention and the bestmeans I know of carrying the same into practical effect, I claim Incombination with a boiler furnace having an ofl'take above the rear ofthe furnace chamber and a traveling grate adapted to carry the burningfuel toward the rear of the furnace, a plurality of fuel jet pipesprojecting through the rear wall of the furnace above the grate,adjacent the path of' exit of the stream of furnace gases, and adaptedto deliver jets of pulverized fuel into said gas stream.

In testimony whereof I have signed my name to this specification;

IVARNER LULOFS.

